Many teachers are ill-prepared to apply practices that can both preempt and address challenging behaviors that interfere with academic instruction. We evaluated the efficacy of a supplemental multi-platform (direct instruction, guided practice, and mixed reality simulations) intervention designed for preservice teachers who do not have opportunities to participate in formal classroom management courses. Efficacy of the intervention was assessed through the quality of classroom management plans, the presentation and implementation of the plan in the virtual classroom, and classroom management self-efficacy. Results indicated that preservice teachers successfully developed quality proactive classroom management plans but struggled to present and implement their plans. However, self-efficacy increased indicating that participants believed they were better able to manage classroom behavior than they did prior to the intervention. Implications of these outcomes are discussed with an emphasis on how adequate opportunities to practice acquired classroom management skills are included in budget-challenged teacher preparation programs.